Biochar

Biochar is a carbon-rich solid produced by pyrolysis of biomass under partial or complete exclusion of oxygen. The process converts ‘labile’ carbon in biomass, carbon that is easily degraded and recycles continuously in the biota, into ‘recalcitrant’ carbon which resists degradation and can sequester carbon on soil for centuries.

The product is identical to charcoal, except it is primarily used for soil amendment purposes. However, it has myriads of applications like cleaning water, reducing odor, adsorbing toxic pollutants on soil to name a few.

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Courtesy of Biochar Solutions Inc.

 

Lists of applications of Biochar

  • Soil Amendment
  • Greenhouse Growth Media
  • Land Reclamation/Remediation
  • Oil Sands Process-Affected Water Treatment
  • Lake De-eutrophication
  • Filter Media (Gas/Liquid)
  • Air emission control
  • Carbon Sequestration
  • Nutrient-enriched soil supplement

History of Biochar

Biochar is found in soils from around the world. It can be formed as a result of natural vegetation fires and has also been created and used by humans in traditional agricultural practices in the Amazon Basin of South America for more than 2,500 years which are locally termed as Terra Preta de Indio – The Amazonian Dark Earths. The late Dutch soil scientist Wim Sombroek (1934-2003) was instrumental in bringing the significance of these soils to the attention of the world over four decades ago. Intensive study of biochar-rich dark earths in the Amazon (Terra Preta), has led to a wider appreciation of biochar’s unique properties as a soil enhancer and more recently as a potential carbon sequestration media/agent.

Impacts of Biochar

Crop and Soil Impacts

  • Enhances crop productivity
  • Improves soil tilt (compaction), fertility, water retention
  • Reduces soil erosion
  • Reduces nutrient leaching
  • Reduces fertilizer runoff
  • Reduces need for frequent fertilizer inputs (Improves fertilizer efficiency)
  • Reduces soil acidity (cheaper alternate to conventional expensive liming)

GHG Impacts

  • Nitrous oxide emissions reduced by 50-80%
  • Some evidence of methane suppression
  • Soil carbon pool

Water Quality Impacts

  • Biochar strongly adsorbs phosphate
  • Reduces leaching of nitrogen and phosphorus

Microbial Population Impacts

  • Provides high surface area and porous network for microbes to flourish

Negative Impacts* (Potential Risks Associated with unsafe Biochar)

  • May contain Polycyclic Aromatic Hydrocarbons (PAH), Dioxins, and Furans (PCDD/F) – Process related origin
  • May contain heavy metals – Originating from contaminated feedstocks
  • May induces Soil Toxicity
  • May lead to the Bioavailability and Translocation of Toxic substances (PAH, PCDD/F)
  • Potentially detrimental to specific soil microbial fauna

*It is therefore very important to formulate optimum feedstock quality threshold and safe pyrolysis process operating boundary for the production of consistent and safe quality biochar.

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